Epic! Guitar Hero - Double Neck Guitar... Fail

2015 marks the 10 year anniversary of the pop culture phenomenon Guitar Hero. You remember, the video game that became more popular than the musical instrument it only vaguely succeeded to imitate? What better way to celebrate its decennial than to cannibalize two working guitar controllers and build them into a single double neck guitar!?

I started this project back when Guitar Hero still ruled the video gaming universe, but I just couldn't get it to work so it was slowly forgotten and relegated to the back of the closet. But now it's time to dust it off and reveal it to the world!

My approach was different than simply gluing two guitars together and having them continue to function as individual controllers (i.e. the bottom guitar playing bass while the top plays lead guitar). My goal was to merge two guitar controllers by soldering their wiring harnesses together and have them function as one! The idea was that doing so would allow one user to play either and/or both guitars during a song.

The successful completion of this project would have likely obliterated Guitar Hero high scores around the world due to its sheer face-melting awesomeness! But I just haven't been able to get it working... yet.

This Instructable lays out my attempt at making a double neck guitar from two working Guitar Hero guitars for the Xbox 360 platform. My assumption is that this would work in a similar manner for other console platforms.

Back when this all began, I didn't find any documented successful double neck conversions such as mine (not to say there weren't any, though). Even now, finding comparable double neck guitar mods was pretty difficult. I had to go way down, into the depths of the internet to find anything. Even then, details about how to successfully complete the project were scarce or non-existent. Over the years there have been a few Youtube videos that have popped up claiming to be double neck guitars, but most turned out to be just two guitar controllers glued together and not acting as one controller.

Here are a few successful projects I was able to dig up recently, but they were created around 2008.

Double Neck Stratocaster for Rock Band (Xbox 360)

Les Paul PS3 & Xbox 360 Double Neck

SG Double Neck

I had two of the white Gibson Explorer guitars and to avoid confusion going forward about which guitar I'm referring to, Guitar 1 will reference the main/uncut guitar, and Guitar 2 will reference the secondary/cut up guitar.

I cut out a stencil to determine where to mate the two guitars. I wanted the two necks to be parallel and the strum bars to be aligned vertically. Once those constraints were met I moved Guitar 2 over until its "point" just touched Guitar 1. I did this to simplify the modification since I would only have to cutout one section from Guitar 2. From there, I marked the overlap line on the stencil and then transferred that to Guitar 2. The guitars had a beveled edge so I made sure to account for that in my measurements and material removal.

The second and third images show the disassembled Guitar 2 after it has been cut. Disassembling the guitar before cutting was crucial to avoid accidentally cutting into a circuit board or through any wires. When I was cutting through the guitar, I was conservative knowing that I could always cut away more material, but would have a difficult time adding extra material or filling in space if I cut away too much.

Because of where I chose to cut Guitar 2, I had to remove the whammy bar so I was really banking on the whammy bar for Guitar 1 to work!

I used two part marine epoxy because I already had some, it dried white, and was more than strong enough to glue the two guitars together. This was the easiest step!

Going into this project, I had no idea if wiring these two guitars together would work. I hypothesized that if I wired the fret buttons and strumming switch of the additional guitar in parallel to the original guitar, a player could use either set of fret buttons or strum bar while playing the game.

Since the goal was to make the two guitars act as one controller, I needed to merge the information traveling from both guitars and send that through just one USB power cord to the Xbox 360. I felt the best option was to try to power Guitar 2 from the power cord of Guitar 1 so I started by cutting the power cords inside the guitars. The power cords consisted of several smaller color coded wires. The internal wiring of Guitar 2's power cord wasn't long enough to reach all the way over to Guitar 1, so I soldered extension wires to reach Guitar 1. Then I soldered the internal power cord of Guitar 2 and both sections of Guitar 1's power cable together. This resulted in Guitar 1 having the same wiring schematic as before its power cable was cut, except that Guitar 2 was then also powered by the same cord. When I tested the double neck guitar, both power indicators turned green indicating they had power, but Guitar 2 had no functionality at all. So I removed the power cord splice and went back to the drawing board.

The only other option I could think of was to splice the strum bar and fret buttons of Guitar 2 into the wiring of Guitar 1. In essence, this would trick the Xbox into thinking there was only one controller, but that controller would have twice as many buttons (in the form of Guitar 2). I made unique markings on the ribbon for each individual wire to ensure that when I spliced it into Guitar 1 I hadn't inadvertently reversed the connections of the wires. Then I soldered everything up.

After all the solder fumes had been evacuated from my nostrils I plugged the double neck guitar back into the Xbox 360 and. . . it still didn't work. FAIL. But it was an improvement over attempt number one. This time Guitar 1 functioned normally, but for Guitar 2, the strum bar only worked in one direction and had very sporadic fret button function. Some of the fret buttons would would activate different colored fret buttons and some would just do nothing at all.

After all that work, it was a major let down. But attempt number two did offer a glimmer of hope sitting at the summit of an uphill battle wrought with extensive troubleshooting and uncertainty.

Despite the lack of success in the past, it's time to "exorcise the demons"! I'm looking forward to giving this project another attempt at EPIC success and making this axe shred!

Here's a list of some things that I'll have to troubleshoot to make that happen:

• Is a fix as simple as checking my solder joints and properly insulating them using heat shrink tubing? Either way, heat shrink tubing will now be the status quo for all solder joints going forward.

• Is the power cord splice method truly not possible or did I make a mistake somewhere?

• It depends on how the Xbox 360 reads the incoming information. Does it recognize the second controller from just one USB input? Does it get confused by the dual signals from one USB input?

• Where did I put that whammy bar from Guitar 2!?!? I might have to make a custom whammy bar since it was not very practical to use the lone whammy bar located on Guitar 1 while playing Guitar 2.

Any ideas or advice for how to make this project a success is welcome! Should I just scrap this one and attempt a wireless double neck guitar!?!?